Apparatus for the control of highway crossing signals



P 1943- R. M. LAURENSON 2,328,656

APPARATUS FCR THE CONTROL OF HIGHWAY CROSSING SIGNALS Filed Sept. 5, 1942 INVENTOR HIS ATTORNEY BobePiMLaanenmon.

and.

Patented Sept. 7, 1943 Robert Laurenson', .E hart, I d-J lass gno to Y TheiUnionSwitcha d si n l'flo nanmzSwiss;

vale "P H a, corporation ofPennsylvania' jdy'invention-relates to. apparatus for :thecontrol .of .higliwaylcrossing signals, .and has particular-reference to :the organization'iof such apparatus into novel :and improved highway crossing signal control systems .of the classin- .oorporating lcoded track. circuits. More partic- :ularly, my invention relates to highway crossing signal control systems incorporating 'coded track circuits of the class disclosedinxmy copending application for Letters .iPatent of the United :States, Serial No. 406;995,.fi1ed. August 15, @1941, ior Coded track circuit system of railway signaling;

In the said copending application, I disclosed prising a source .of power connected to the r-ails in multiple with the track relay Tat-the entrance -end.of a section, and exit. end apparatus-:compris ing another-source oi current and a detector re ilay connected alternately to the rails'at theexit end .of (the section. The arrangeinent is such .lthat when theL-exit end source is connected to the rails, v.the two sources oppose each other in the track relay winding, and whencthe exit end source is disconneot'ed-from the track rails, both the track relay and the detectorrelay-are energized :by current supplied from the entranee.

.encl source. V In the application of a-system of the type-described tothe controlofahi'ghway crossing signal positioned at the crossing intermediategthe two ends of a track sectiommeansmustbe pro- 'viderl to terminate operation of the crossing signai aftera train clearsthe' crossing, without initer-fering with the 'controlvof the wayside signals governing traffic in theseotion 'It'is, therefore,

an object of my present invention-to provide 'means in a system of the tYped'iselGsedin-my said copending United States application, "Serial No. 406,995, for-adapting suoh's ystem to the eontrol of highway crossin'g signals. 1

Another object of my invention is the provision of a novel and improved l iighway crossing signal system incorporating coded track-circuits arrangecl'to effect operation of aerossing signal Without use of line wires.

An additional object is to provide a novel and improved highway crossing signal control system.

a In practicing the invention, the abovesmen- "tioned and other important objects Land char.- -acteristic features offlmy invention whic'h wiil csari tlon. e atta ned-bi d .eornonatins an anx- -i isry relay into, th t a k Ila-ar an m nt sh wn my on ssing nlt States applic ion, Ser al .No 406,995; by militias means re.- sncnsivetozt amc in tn n xtadia ent t ack sinonitin advaneeof t rossin r at tim s connecting the an liars elay otne tails of its associated. 91101 .11 lieu of the d t ctor r lay and :exitendsenr :oftnetn-irouitand y .cnntrollin t r es... ng sisnalby boththe auxiliary relayan the detector relay. i

lsnal describe one former anpara nsemhody- 7 ins :myinventien, nd sha l t n p in out the novel improved .iorms vof noded track circuits incorporatingapparatus 'for governing approaohnon :troile'd functions without use of line Wires; This .apparatus includes entrance end apparatns com- ,caturesther of incleims. a 'Theac omnanying= rawingis a dia rammatic stretch of railway track over which traificmoran lly dnoves in "the direction indicated .qbyan renew or fire-m left to :right-asyviewed in the d awin The rails I and 1111 are. divided-by 1:1stunteclimntsa-I! into a plurality o Successive ad oinin track sections. of which only one secti n, E F, is represented complete in the drawin section turnis divided by joints :2 11. .1 it cut scction flotation 'Ea into subsections .ZT .:an. l fiubsectionn z'lis intersected at :grade ariiac nteto :itsyeXit and 'Ea'loy. ai'iighv'vaylfl, and o te zaasiiacent to such intersection is a. highcrossing awarning signai such as an electric rbel'lj Signal 25S is-contnoiled by a relay and is provided with an operating .circuitwhich extend rimmoneeterminai B of a suitable source .eurrentthrougnrback contact 9 of relav and the oPer-ating' element of signal XS to .ter-

a imal: .6 of the same source of current.

Theioneration ofmailwaytrafiic in section -i;s, govcrnedby; a wayside signal Scpositio'ned at the .en-tBa-nce end E of thesectionr This signal and the-highway crossing signai K8 are controlled hroude traek circuit apparatus provided tor subsections 2T 3T andPar-ranged tomoooperate zapnovelzmanner. The specific form of the track circuit apparatus gprovided for subsection -.:3T.=is immaterial te-the present invention and it .may take 1 any -riesi'red dorm which incorporates means forcdetecting operation of atrack relay "by seeded energy received from the rails .of the sec- ;tion; a'c' torftne purposes of the Ipresent descriptionsitzis deemed? necessary to show only atypical become readily apparent from the 'foilowirigudei15 .iaform encoded track circuit comprising abatteny J0 intermittently connected to the rails -atwthle exit. 633.? lot the jsuigsectioniover-a eontact iii of relay HR. is held picked up when and only when,

relay 3TB. responds to coded energy received from V the rails of its subsection.

Referring now to subsection 2T, the'apparatu's at the entrance end E is arranged in accordance with the disclosure of mycopending. United States application, Serial No. 406,995; It cornprises a track relay 2TB and a resistor l2, connected in series across the rails; with a track battery [4 and another resistor It also connected in series and the two latter elements being connected in multiple with the first two. Relay ETR is of the'polar biased type and bears an arrow pointing from left to right as viewed" in the drawing to indicate that it -i s'responsive to our- -rent' of such polaritythat its left-hand termil nalis positive. Battery l4 connected therewith is poled to supply current of such given polarity 'to'the'relay, Relay 2TB has associated there with decoding apparatus, indicated conventionally in the drawing and designated by the referencecharacter DA, arranged to govern the associated wayside signal S in the usual manner. That is to say, the control is such that signal S willbe caused to display itsstop indication 7 wheneverrelay 2TB, is either steadily picked up -or released, and will be caused to display a less restrictive aspect whenever relay ZTR responds to coded energy. 1

The exit end apparatus for subsection 2T comprises another battery I G, a detector relay DRfa slow-releasing repeater relay DPR, an auxiliary relay AR,and a constantly operating coding deviceor coder ZCT. This apparatus is also arranged in accordance with the disclosure of .my copending United States application, "Se- --rlal No. 406,995; When'relay HR. is picked up in response to the operation of its associated track relay 3TB by codedenergy received from the rails of its associated subsection, either a battery [6 or theyrelay DR is connected across the rails of subsection 2T through from contact 22 of relay HR according as" contact 20 of coder f 2CT is'in its front or" back position,respectively, a resistor 2| being includedin series with the battery 16..- Battery IB is poled in such a manner that when it is connected with the track rails, the two batteries ld and I6 buck or oppose each other in the windingof track relay 'ZTR."

Relay ZTR is therefore "deenergized when battery' I6 is connected in circuit with the track rails. .When, however, battery l6'is disconnected from the rails, then track relay 2TB and dewtector relay DR, become energized,in multiple, "by current supplied from battery l4. 1

Detector relay DR controls its associated slow releasing repeater relay DPR through the medium of a decoding transformer ZDT in such a manner that'relay DPR is energized momentarily each time relay DR is picked up or released.

-Relay DPR, thus; detects a coding operation of relay DR and is held steadily in its picked-up position by its slow releasing characteristic whenever relay DRis intermittently-picked up and released. 1 l P In accordance with fthepresent inventiomre- AR to the rails of subsection 2T in lieu of bat tery IE or relay DR. This is effected by an obvious path including the back point of contact 22 of relay HR and the winding of relay AR. It

follows that when relay HR is released and subsection ZT is vacant, relay AR is energized by current supplied from battery I4.

' Signal control relay'XR. is governed jointly by relays DR and AR, and is energized over an "obvious circuit whenever front contact 24 of relay DPR or front contact 25 of relay AR is closed. 7

' When section EF is vacant, the apparatus is in its normal condition as represented in the drawing. In this condition, relay HR is energized in response to the operation of relay 3TB, by coded' current received from the rails or" its subsection, and as a result the track circuit apparatus of subsection 2T functions to operate relays 2TH. and DR at a rate corresponding to therate'of. operation of coderZCT. Relay'DPR is therefore energized and it in turn energizes relay XR so that signal XS isdeenergized.

When a train enters subsection 2T, the coded currents supplied from battery lii'and battery i l are shunted away from relay 2TB, and that :relay assumes its released position. Relay DR likewise assumes its released position since it is also shunted by the-train. -Repeatcr relay DPR accordingly releases and in turn releases relay XR to cause thatcrelay to complete the energizing circuit of signal XS. This condition of the apparatus is maintained until tion 3T. a

When this happens, relay 3TB is shunted and the train enters secassumes its released position, whereupon relay HR'becomes deenergized and releases to open its front and close its back point of contact 22. This action disconnects battery l5 and relay DR from the rails of subsection-2T, and connects auxiliary relayrAR, to such rails. ,jThe auxiliary relay is of: course shunted and remains released as long as any part of the train occupies subsection 2T. Whenthe rear end of the train leaves subsection 2T and removes its shunt, relays 2TB and AR become steadily energized by current supplied from battery E 2, and: as aresult both relays pick up. This steady energization of relay ZTR has no material effect'upon the apparatus controlled thereby and hence does not aife'ct signal S, but

relay AR in picking up energizes relay XR and hence terminates operation of signal XS After the train 'vacates subsection 3T, relay 3TB. responds to the coded current available in the rails and causesrelay HR to pick up. This iactiondisconnects relay *AR from and connects battery it and relay'DR to the rails of subsecg-tion 2T.- 'Relay-ARaccordingly releases, but with the track circuit apparatus of subsection 2T restored to its normal condition, relays 2TB and DR- -intermittently pick up and release and relay DPR accordingly picks up." The crossing signal control relay KR, as indicated, is preferably provided with a slow releasing characteristic, selected to maintain it picked up duringthe interval that elapsesv between the release of relay AR. and the picking up of relay DPR, sothat the crossing signal will not be operated momentarily when the train vacates subsection 3T. j

From the foregoing description, it is readily apparent that I have provided a novel and improved coded track circuit system for controlling a highway crossing signal positioned; at acut- .section-1ocation ina track, section. This system islcharacterizedbythe fact that no line wiresare required to terminate operation of the signal without effecting operation of the wayside signal governing railway trafiic in the section.

Although I have herein shown and described only one form of apparatusfor the control of highway crossing signals embodying my invention, it is understood that various'changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination with a stretch of railway track including a track section having a portion provided with a track circuit comprising a source of current connected across the rails at one end of the section and a relay connected intermittently to the rails at an intermediate point in the section over a circuit including a constantly operating contact of a coder device, another relay, means governed by traific on another portion of said section for at times disconnecting the said circuit connection of said first relay from said track rails and constantly connecting said other relay to said track rails, and means governed jointly by said first and said other relay.

2. In combination with a section of railway track having a portion provided with a track circuit of the class comprising a first source of current and a first relay connected in multiple to the rails atone end of the section and a second source and a second relay connected alternately to the rails at an intermediate point in the section according as a const'antlyoperating coding device operates its contacts to one position or the other, said first and second sources being poled in such manner as to oppose each other in the winding of said first relay, a third relay, means governed by traffic conditions on an advance portion of said section for at times disconnecting said second source and second relay from said track rails and connecting said third'relay in circuit with said rails, and a signaling device governed by said second andthird relays.

3. In a railway signal system of the class wherein a signal at the entrance end of a track section for governing traflic in, saidsection is controlled by a track circuit comprising a first relay and a first source of current connected in multiple to the rails at said entrance end and a second relay and a second source of current connected alternately to the rails at an intermediate point in said-section over a circuit path including a constantly operating contact of a coding device, said second source being poled to oppose said first source in the winding of said first relay, the combination of an auxiliary relay, a track circuit for an advance portion of said section, means governed by said advance track circuit for at times constantly connecting said auxiliary relay to the rails of said section in lieu of said second source and second relay, and signaling meansgoverned by said auxiliary relay and by said second relay.

4. In combination, a section of railway track intersected intermediate its ends at grade by a highway, a highway crossing signal at such intersection, a track circuit provided for a given portion of said section comprising a track relay and afirst source of current connected in multiple to the rails at one end of said section and a second relay and a second source connected alternately to the rails adjacent to saidintersection, a signal governing railway trafiic in said section and controlled by said track relay, a track circuit for a remaining portion of said section, an auxiliary relay, means governed by said remaining portion track circuit for at times constantly connecting said auxiliary relay to the rails of said given section portion in lieu of said second source and second relay, andmeans governed jointly by said second relay and said auxiliary relay.

ROBERT M. LAURENSON. 

